struct editor: auto-format the definition on save

After a successful declare, re-fetch the canonical struct_source and put it back
in the editor, so the normalized layout/types show immediately instead of only
after re-selecting the struct from the list (e.g. a pasted one-liner becomes
multi-line, 'unsigned long' -> 'unsigned __int64'). _loaded_src is updated to the
formatted text so it isn't considered dirty. Pilot check. full suite 92/92.

2 files changed, 23 insertions, 3 deletions

diff --git a/idatui/app.py b/idatui/app.py
index 271d8f7..32a0698 100644
--- a/idatui/app.py
+++ b/idatui/app.py
@@ -1334,9 +1334,18 @@ class StructEditor(ModalScreen):
             return
         m = re.search(r"\b(?:struct|union)\s+([A-Za-z_]\w*)", text)
         name = m.group(1) if m else None
-        self.app.call_from_thread(self._after_save, name, err, text)
+        # On success, pull the canonical source back so the editor shows the
+        # normalized layout/types (auto-format on save).
+        formatted = None
+        if not err and name:
+            try:
+                formatted = self._program.struct_source(name)
+            except Exception:  # noqa: BLE001
+                formatted = None
+        self.app.call_from_thread(self._after_save, name, err, text, formatted)
 
-    def _after_save(self, name: str | None, err: str | None, text: str) -> None:
+    def _after_save(self, name: str | None, err: str | None, text: str,
+                    formatted: str | None) -> None:
         if err:
             # IDA's parse error is usually empty/cryptic; name the likely cause.
             msg = err.strip()
@@ -1348,7 +1357,13 @@ class StructEditor(ModalScreen):
             self._set_status(f"save failed — {msg}", error=True)
             return
         self._loaded = name
-        self._loaded_src = text.strip()  # editor now matches the saved type
+        if formatted:
+            # Reformat the editor to IDA's canonical layout (keeps cursor at top).
+            ta = self.query_one("#se-edit", TextArea)
+            ta.text = formatted
+            self._loaded_src = formatted
+        else:
+            self._loaded_src = text.strip()  # editor already matches the saved type
         if getattr(self.app, "_dirty", None) is not None:
             self.app._dirty = True  # unsaved-to-disk until Ctrl+S in the app
         self._refresh(select=name)
diff --git a/tests/test_tui.py b/tests/test_tui.py
index e990bef..6a8f898 100644
--- a/tests/test_tui.py
+++ b/tests/test_tui.py
@@ -180,6 +180,11 @@ async def run(db):
             await wait_until(pilot, lambda: any(s.name == sname for s in se._structs), 15)
             check("Ctrl+S declares a new struct",
                   any(s.name == sname for s in se._structs), "not created")
+            # save auto-formats the (one-line) definition to canonical layout
+            await wait_until(pilot, lambda: "\n" in ta.text, 10)
+            check("save auto-formats the definition in the editor",
+                  ta.text.count("\n") >= 3 and f"struct {sname}" in ta.text
+                  and not se._is_dirty(), f"text={ta.text[:50]!r}")
             # update it (add a field -> member count grows)
             idx = next(i for i, s in enumerate(se._structs) if s.name == sname)
             se.on_option_list_option_selected(type("E", (), {"option_index": idx})())